A heating and hot water supply system disclosed in the following PTL 1 includes a heat pump for heating a liquid heat medium, a hot water storage tank, a tank-heat exchanger provided on a lower part in the hot water storage tank, a room heater, a circuit for circulating the heat medium to the tank-heat exchanger, and a circuit for circulating the heat medium to the room heater. This heating and hot water supply system performs room-heating by circulating the heat medium heated by the heat pump to the room heater and stores hot water in the hot water storage tank by circulating the heat medium heated by the heat pump to the tank-heat exchanger.